Process of refining zinc.



No. 893,415. PATENTED JULY 14, 1908.

R. ZIESING. PROCESS OF REFINING ZINC.

APPLICATION TILED FEB. 27, 1907.

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UNITED STATES PATENT orFioE.

RICHARD ZIESING, OF CLEVELAND, OHIO, ASSIGNOR OF ONE-HALF TO THE GRASSELLI CHEMICAL COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

PROCESS OF REFINING ZINC.

Specification of Letters Patent.

Patented July 14, 1908.

Application filed February 27, 1907. Serial No. 859,607.

To all whom it may concern:

Be it known that I, RICHARD ZIEsING, -a citizen of the United States of America, and a resident of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Im rovements in Processes of Refining Zinc, 0 which the following is a specification.

My invention relates to improvements in rocesses of refining zinc and more particuarly to the separation of zinc from such metals as lead and silver.

It has long been known that zinc may be separated from metals havin greater specific gravity by reducing the spe ter to a molten condition and allowing the heavier metal to The zinc, under these conditions, may be distilled at a temperature which will not affect. the heavier metal, although in practice it is found that the process is frequently accompanied by the distillation of appreciable percentages of the contaminating metal or metals. The prior processes of separation have been carried on 1n the ordinary or slightly modified Belgian furnace and certain precautions, such as reversely inclining the retorts and cooling the same, have been resorted to in order to reduce the percentage of contaminating metal to as small an amount as was practicable. Due partly to the fact that the heat is ap lied from below to the retorts, and the lea or other con- I taminating metal is thereby freguently in a state of ebullition, the process 0 separating the zinc therefrom is one which must be carefully controlled by skilled employees, in order to secure satisfactory results, otherwise the percenta e of contaminating metal may rise to an un esirable or prohibitive amount. In view of the conditions requisite for the satisfactory separation of these metals, I have devised an improved method and apparatus for practicing the process in question.

Briefly stated, the rocess consists in directing heat against t e-r'etorts or rece ta- 'tempera'ure to maintain rapid distillation of the zinc. I

The preferred apparatus for practicing my.

improved process consists of a down-draft in order to show the flue-connection.

furnace, wherein the retorts are disposed upon beds or su porting illars of non-conducting m ateria Specia ly formed retorts adapted to retain the bottom ortions of their contents in a relatively coo condition, may be employed in connection with my improved furnace. K

Further details of the foregoing will be readily gathered by making reference to the accompanying drawings showing one means of practicing my invention, wherein,-

Figure I is a transverse sectional view through the furnace, a retort and condenser; the furnace bed being partially broken away Fi .II is a longitudinal sectional view taken thrdilgh one section or division of the furnace. Fig. III is a detail in longitudinal section of the flask and rearward portion of a self-sealing retort, and Fig. IV is anend view of a retort specially adapted for the process herein set forth.

Throughout each of the several figures of the drawings, I have employed the same character of reference to indicate similar parts.

In the drawings I have depicted one section of a small furnace embodying my improvements and adapted for the practice of my invention. Therein is shown a downdraft gas-fed furnace, wherein the distilling retorts a are carried upon a recessed perforated bed b; said recesses I) being adapteil suitably toprotect the bottoms of theretorts against the distilling heat maintained in the combustion chamber a. The perforations b 'in said bed connect with sub-fines (1, leading i'earwardly to the main flue 6 connecting with the chimney-stack. Front and back buck-stays f support the furnace walls 0, and the dome c of the combustion cham her, while upon the rear buck-stays are r ovided arms f carrying the gas main 9. aid main g is provided at intervals with intermediate connecting, pipes g and air-mixers g opening within the combustion chamber.

Any suitable "retort may be em 'loyed in my improved furnace, but preferably I use a retort generally oval in cross-section and provided with thickened bottom portions (1,

.as shown in Fig. IV. These heavy walls in protect. the contained metal from relatively igh temperatures. Thus all tendency towardebullition of the metal is overcome,

while the, thinner upper walls of the retort permit the penetration of heat from above to insure the surface distillation of the zinc.

5 Instead of the foregoing construction, I may employ other retortssuch as the ordinary .t pes shown on the left hand side of Fig. II? or those of the ty e set forth in my Patent No.818,070, date April 17th, 1906, wherein the thickened bottom walls are provided with an air shield or cushion, and may be cooled by the circulation of air adjacent to the bottom portions.

, The rear portion ofthe retort preferably is provided wlth an opening a. for'charging in ,the spelter,,which opening normally is sealed with a plug of fire clay a sealing. Luted into the forward end of the retort, is

f a suitable flask or condenser h, which preferably isprovided with an interior rim h adapted to retain the zinc from flowing back, as it is distilled over from the retort, and from which the zinc ma be removed from time to time. Thecon enser is readily removed from the retort whenever it becomes necessary to collect therefrom the accumulated lead, silver or other contaminating ma-.

terial. 3

My im roved process may now be readily explaine and understood, as practiced with the improved furnace above described. The combustion chamber. being suitably heated from above, by means of the gas burners, and the retorts being. charged with spelter' to aproximately the-level shown in t e drawings. t will be appreciated that the lowermost 1 portions of said retorts necessarily are shielded from the temperatureof the comsufficient to insure the Y distillation of zinc. This, of course, maintains the bodies of metal within the retorts in highly fluid conof the retort containing the molten lead remains relatively cool, and is subjected in 5 lesser degree to the destructive action of that usual 1 support from front a a Or again, the. opening a, may extend diagonally below the 'normal level of the metal, as shown in Fig.. III, thereby making the retort entirely selflonger continuation of the process, by re bustion chamber, which preferably is just On the other hand, the surface met metal. Under these conditions, the smallest I fraction of a percent.-of contaminating metal,

will be found in the purer zinc collected in the condensers. i

It will be appreciated that both the construction' of my improved furnace, providing protective shields recessed to contain 'asbestos, ground fire-clay or other suitable material, and the construction of the specified retorts, mutually contribute to the success of 7 5 the process as practiced, but either of these' features may be inde endently employed in connection with suitable means for directing I the distilling heat from above. I

By reason of the fact that the retorts in 0 my improved furnace are supported throughout their entire length, as op osed to the n8 rear walls of the furnace, it is possibleto increase the length and diameter of the .retorts indefi- 5 nitely, which of itself serves to economize space, fuel and labor. Asjzthus disposed, the retorts are rendered self-sealing against minor perforations orleakage-s since themetal flowing through such perforation will come into contact'with the relatively cooler body of the sup oiting shield, the fire-clay or asbestos and so 'difying, seal such accidental opening. Where additional horizontal rows or tiers of the retorts are to be used, however, it is preferable to employ retorts with'heavyheat resisting bottom portions, of the types herein referred to, supported from the front alrlid rear in the usual manner and thus saving t e shiel g members.

in attendingxthe furnace, andin minimizing,..;

metal, upon the retorts, while permittin peated charging of the retorts.

Having now described the preferred ineans and process contemplated by my invention, I

claim as new and desire to secure by Letters -Patent, the following 1. The herein described process of separate I :in zinc from metals possessing greater spe c' c gravity, consisting in dlrecting heat from above against the receptacle containing the zinc-alloy, sufficient-tomaintain thebody of metal in a molten condition and insure surface-distillation of the zinc, substantially as set forth.

2 The hereindescribed process of separatindg zinc from, metals possessing greater spec' c gravity) consisting in dlrecting heat a ain'st thegigeceptacle containing the zinca oy sufficient to maintain the body of metal in molten condition, while insurin the distillation of the zinc, and shielding rom heat the ortion of the receptacle wherein the.

ad of greater specific gravity collects, substantially as set forth.

gpace otherwise required for separate 100' m V The process as herein outlined, accom f lishes economies in reduced costs of labor,

2;. The herein described process of refining zine l'rom an alloy containing lead, which consisls in directing heat from above against the receptacle containing the zinc-lead alloy, sullieient to maintain the body of metal in a l'reeh molten or fluid condition and meanwhile insure surface distillation of the zine, whereby the lead settles to the bottom of the receptacle and the zinc is vaporized, and shielding the lower portion of the receptacle containing the lead from heat, substantially as set forth.

4. A method for separating zinc from metals of greater specific gravity, consisting in charging the alloy into retorts, heating the 15 retorts from above to a temperature efl'ecting surl'ace distillation of the zinc, permitting the heavier metal to remainquiescent in a constrieted portion of the retort, shielding such portion from excessive heat, and collecting 20 the zinc as it is distilled, substantially as set forth.

Signed at Clarksburg, W. Va, this 25th day of February, 1907.

RICHARD ZIESING.

Witnesses:

E. B. TEMPLEMAN, ANNIE HUGILL'. 

